I dug it all by hand :-) :-) except for the inverted swastika and a small "pond on the extreme left part of the land...
I think the willows will have exacerbated the forms, but mostly I just laid down wood, grass, dug trenches and put the earth on them (a bit like hugelkultur) and slowly widened, deepened the trenches.. there's a river running paralell and I dug a wide trench paralel to this hoping to use the river to irrigate occasionally... it's very meditative "work" perfect for mulling a book over :-) :-) if you use the link provided by a poster below and go on streetview, you'll even be able to see I carved out the word UBUNTU :-) :-)